PHOTOCATALYSIS IN AQUEOUS-SOLUTION WITH SMALL TIO2 PARTICLES AND THE DEPENDENCE OF THE QUANTUM YIELD ON PARTICLE-SIZE AND LIGHT-INTENSITY

A model for the kinetics of photocatalytic processes on spherical TiO2 particles is developed. The quantum yield for the photooxidation of o rganic molecules by, oxygen in aqueous solution is derived for two cas es. In one case the yield is limited by surface recombination, in the other case by a reverse reaction of electrons with the first oxidation product by holes. It is shown that the quantum yield increases with d ecreasing illumination intensity and size of the particle.